Very well inspired platformer, albeit an odd topic to make a game on. mechanics and such are nice, the graphics and music are great for the mood and the game looks all around nice. It is a very well made game, with most controls being very easy to adapt to and deal with.
Most. I might be the only person with this problem, but I have no idea how to use the gravity shifter. It doesn't make a lick of sense, and it's getting me killed A LOT. The instructions are very unclear on using it, and when I tried just pushing buttons it never worked with a consistent command. It was particularly frustrating, but this was the only fault I could find with the game, except for maybe a few small control commands that were left out of the tutorial (i.e. the Strafe command).
All in all, fantastic job, but please try to be clearer when giving controls.